Flexible hoses have been utilized in many different applications involving transporting gases, liquids, and even solids, which are often in the form of particulate matter. Although most hose applications involve pumping material under pressure from a first location to second location, flexible hoses are frequently utilized in conjunction with electrical motors that create suction or negative pressure to create a vacuum.
Vacuum hoses have numerous applications, such as the intake vacuum to supply air into the manifold of a combustion engine, the pump and filter of a swimming pool's water cleaning system, industrial uses for materials processing or manufacturing as in the production of composite parts that are vacuum bagged and cured in an autoclave, or in scientific laboratories where a vacuum is necessary for experimentation.
Perhaps the most common application for a vacuum hose is its use in conjunction with the ordinary household vacuum cleaner. The home vacuum cleaner may be the most common usage of flexible vacuum hoses or perhaps may simply be the first application that comes to mind, but such vacuum cleaner usage may also be found in many commercial areas. Industrial vacuums are common in building construction for clean up after cutting operations or for water removal, and vacuums are even commonly truck-mounted to provide large scale, mobile vacuum capabilities with wide-ranging possibilities including sewage removal from cesspools to removal of litter, leaves, or pine needles from a golf course fairway.
In the home vacuum application, and particularly for industrial vacuum applications, the hose may need to be of substantial length during the cleaning operation to be practical or efficiently utilized. However, a substantial length of hose attached to a vacuum canister unit, or to another body which supports a vacuum motor, becomes cumbersome to handle and transport after vacuum operations have been completed. Moreover, during such operations when a portable vacuum unit merely needs to be relocated to another area requiring its use, the length of hose may be unwieldy and difficult to handle because of its bulk, and may hamper or degrade the overall efficiency of the cleaning operation.
These considerations have led to the development of stretch hoses, which provide greater convenience in the transporting and maneuvering of vacuum cleaners and hoses. While a stretch hose may simply be a hose whose construction permits a user to apply a force, which may be minimal, to increase the nominal working length of the hose, self-extending hoses are biased to extend to a greater working length without any effort on the part of the user, other than perhaps releasing a restraining mechanism that retains the hose in the retracted condition.
One example of a self-extending hose is shown by U.S. Pat. No. 6,948,527 to Ragner. Ragner discloses a hose design which has a biasing spring that exerts an extending force on the cover material, and through the use of a pressure control mechanism, can utilize suction to retract the hose against the spring biasing. Ragner suggests the possibility of incorporating conductors to supply electrical power to the end of the hose, but defers offering a solution or configuration for such conductors.
But U.S. Pat. No. 5,555,915 to Kanao offers a hose design whose construction incorporates a steel reinforcing wire as well as a conductive wire that is obtained by intertwisting a large number of copper fine wires. Kanao suggests a configuration whereby the reinforcing wire and conductive wire are side-by-side, with the hose cover material draping across the wire-pair and having inward folds which permit expansion. Kanao suggests that its construction provides extension/contraction zones that can be extended in the direction of the hose axis by manually pulling the hose, and that its use will result in “little user fatigue.” Thus, the hose is not actually capable of self-extension. The invention discloses herein provides a hose capable of self-extending while incorporating multiple wires capable of providing necessary electrical connections at the user's end of the hose.